Shank stiffener



July 16,'1946. N. Rosi-:NTHAL sHANK 'STIFFENER Filed Feb. 28, 1945Patented July 16, 1946 UNITED STATES PATENT oFI-ICE 2 Claims.

My present invention is a novel and improved shank stiffener for use inthe manufacture of boots and shoes, and is directed particularly toprovide a shank stiffening and arch-supporting feature with specialreinforcements in the archsupporting portion of the shoe.

Heretofore, it has been customary to make shank stiffeners of metalwhich would be tted between the insole and outsole and Would give astiffening and reinforcing effect in the arch of the shoe between theheel and the tread portion of the forepart. Such metal stiffeners wereusually .secured to the heel and extended forwardly in a preformed curveto a sliding engagement at the ball or forward portion of the outsole.

`It has also been customary to have one or more longitudinalcorrugations or ribs formed in a part of the shank stiffener to aid inholding the arch of the shoe in predetermined arc-shape.

My present improved arch stiffener constitutes a double reinforcingstructure wherein a :part of the arch stiifener comprises astrengthening and reinforcing element longitudinally from the heel tothe ball of the shoe, and a second preformed portion with a distinctdisaligned arc structure in the shank stiffener which will automaticallyeffect a supporting and lifting of the lateral or side portion of thearch of the shoe and, hence, constitute a support for the side archportion of the foot of the wearer.

Furthermore, I so arrange and construct my present improved shankstiffener as to provide a reinforcing rib member in a curved formation,defining the area lbetweenthe fore and aft arch and the lateralsupporting feature. In order to secure additional rigidity in thelateral supporting feature, I provide one or more ribs therein, whichribs may be and preferably are of curved contour and may be eitherlongitudinally or crosswise of the length of the stiffener. In eithercase, the side or lateral arc portion of the shank stiffener gives avastly greater and increased lateral arch support to the sole of theshoe in which the stiffener is fitted, as well as to the foot of thewearer, giving a firm support and brace to the lateral arch of the shoe.

Thus, my present stiifener comprises a double reinforcing shoe shankstiffener, having one arc formation for the longitudinal or fore and aftstructure of the shoe, and a divergent and different lateral archedcontour with reinforcements therein for the side or lateral arch of theshoe and foot. Thus, my shank stiffener constitutes a reinforcingelement from the heel to the forepart, and also a side or lateralarch-supporting element at a dierent and much sharper angle,predetermining the contour and form of the shoe and insole at thislateral arch part and, hence, affording support to the foot of thewearer. Thus, my improved shank stiffener has inherent and addedstreng-th by reason of the divergent arched areas of the longitudinaland the lateral portions, the line of juncture between the lateral andthe longitudinal differing arc formations constituting i-tself atruss-like effect or rib which, furthermore, will preferably have adistinct rib formation to predetermine the line of demarcation betweenthe lateral and lengthwise arch and thus constitute a common supportingelement for both the longitudinal and lateral arch portions.

Furthermore, by having the lateral arch of less length than that of thelengthwise arch portion, I secure the benefit of a full support at theheel and on the ball of the forepart of the shoe for the lengthwisestrengthening part, these being fully equivalent to standard archsupports as at present in use.-

Furthermore, by having one or more reinforcing rib structures in thelateral arch itself, greater strength is added and the predeterminedcontour of the shoe itself is permanently maintained.

Referring to 'the drawings illustrating preferred embodiments:

Fig. 1 is a plan View of my improved shank stiffener Vwith thelongitudinal and transverse arc-supporting structure;

Fig. 2 is a corresponding plan view illustrating reinforcing andstiffening convolutions;

Fig. 3 is a plan view illustrating a modification of reinforcingconvolutions;

Fig. 4 is a side View of the shank stiffener of Fig. 1 showing thelongitudinal arc contour, and

Fig. 5 is a diagrammatic view on the line 5-5 of Fig. 1 illustrating theshank stiffener as applied to the insole on a last illustrating thetransverse arc feature.

My shank stiifener may be and preferably is made of metal stamped intolongitudinal and transverse arccurves, which may be varied for theparticular style, design, and size of shoe to which my shank stiffenersare to be fitted. The shank stiffeners as shoWn in the drawings areillustrative of a moderate arc contour both longitudinally andtransversely, which arcs can be greatly increased where desired.

Referring to Fig. 1, the arch stiifener comprises a metal plate l ofappropriate length and contour and, preferably, stamped from sheetmaterial having a heel-engaging portion 2 and an opposite edge portion 3to engage the ball of the shoe sole, which portion 3 may beandpreferably is somewhat larger than the heel part, with a predeterminedlongitudinal curve from the heel part 2 lengthwise throughout asubstantial widthwise area of the shank stiiener to the forepart 3.Holes 5 to enable the shank stiffener to be nailed rmly to the heel ofthe shoe are provided, and the forepart 3 is preferably unattached andis allowed to slide slightly to adjust itself to the contour of the soleand insole during use and to aid in the flexibility of the shoe at theball portion. The transverse or widthwise arc is preferably formed onthe blank during the original stamping-out action, or it may be shapedand curved afterwards, and consists in the transverse arc-shaped areaI!) throughout a substantial extent of the length of the shankstiffener.

As shown in Fig. l, this transverse area IU may be stamped from wherethe heel part of the shank stiffener extends over the heel breast of theshoe, as indicated approximately at I2, Fig. 1, extending to the extremeforepart of the edge 3, as shown at I3, and merging into thelongitudinal arc portion of the shank stiifener I on a curved line, asapproximately indicated at I5, which curved line may be also formed as astiiening convolution or rib.

This rib I5 thus acts jointly to hold both the longitudinal arc of themain part of the stiffener I in its preformed position as well asserving to stiffen and hold the transverse arc portion IIJ in itspreformed position.

My improved shank stiffeners are made for rights and lefts with thetransverse arc portion ID adapted to lift the insole and, hence, supportthe foot of the wearer on the inner transverse arch portion of the shoeand foot, thereby affording a snugger fitting and hugging of the foot,which also facilitates the lasting operation, enabling the shoe uppermaterials to be drawn down smoother and firmer during lasting,

In Fig. 2 I have shown a plurality of reinforce ing ribs or convolutionsto still further hold and maintain both the longitudinal and transversea;

arc-shaped portions of the shank stiffener in their predetermined curvedposition The longitudinal rib 20 aids in holding the longitudinal arcwhile one or more transverse ribs 2`I, 22, and 23 hold the transversearc portion IU in reinforced preformed contour. Additional ribs 23 and24 may be also stamped or otherwise formed in the blank during themanufacturing operations.

In Fig. 3 I have illustrated a single lengthwise curved reinforcedconvolution or rib 25, and various modifications of such reinforcingelement will readily occur to those skilled in this art, the importantcharacteristic of my longitudinal transverse arch formation being thusmaintained to hold the shoe in exactly the shape and supporting contourfor which it is designed.

As shown in Fig. 5, my shank stiifener is illustrated as applied to aninsole 30 between the sewing ribs 3I and 32, which insole is illustratedas positioned on a last 35, the last having a complemental cut-awayportion 36 to cooperate with the lateral arc-shaped edge I0 of myimproved shank stiiener. This construction enables the foot-supportingportion of the insole to be precurved widthwise and to aid in mergingthe corresponding part of the insole with the uplifting adjacent part ofthe upper materials (not shown).

My shank stiffener may be applied to the insole before it is fitted tothe last or may be applied afterward but before lasting so as to thusimpart to the insole the initial foot-supporting feature at the arch ofthe shoe and, hence, of the foot of the wearer.

My improved shank stiffener is entirely within the inner side of thesewing ribs of the insole and shoe and, hence, takes the place of theordinary metal shank stiffener; but in my present improved construction,I provide one or more stiiening elements, such as ribbed convolutions inthe laterally curved part of the shank stiifener, as distinguished fromthe longitudinally curved portion and any longitudinal ribbedstrengthening elements. I believe it to be a distinct novelty in thisart to have stiiening elements in the laterally curved or concavo-convexside portion, whether such ribbed strengthening elements arelongitudinally curved or crosswise.

I claim:

l. A metal shank stiifener of the kind described, comprising alongitudinally curved portion and a laterally extending concavo-convexside portion, said side portion being formed in a divergent line orcurve from the longitudinal curve, the side portion being reinforced.

2. A metal shank stiiener of the kind described, comprising alongitudinally curved portion and a laterally extending concavo-convexside portion, said side portion being formed in a divergent line orcurve from the longitudinal curve, the side portion being reinforced byribbed convolutions extending crosswise of the said side portion.

NATHAN ROSENTHAL.

